This invention relates in general to the storage of material within a rigid container having a closure device subjected to external closure disengaging forces while ejection of said stored material by pressure internally generated within the container exceeding a preset limit is predetermined by the retention force associated with such closure device.
Closure caps on chaff dispensing canisters carried by aircraft are subjected to high external acceleration and deceleration forces during take-off and landing, especially with respect to naval aircraft carrier decks. The closure cap retention force for such chaff dispensers must therefore be greater than the maximum aircraft deceleration forces, anticipated for example during arrested aircraft landing on naval carrier decks. The cap retention force must however be less than the cap disengaging force exerted by internal pressure generated in response to propellant charge ignition for chaff ejection purposes during aircraft flight. The chaff ejection pressure must not, however, be too high so as to avoid dispersal of ejected chaff by an excessive distance defeating its camouflaging function. The generation of excessively high chaff ejection pressure may also rupture or split the chaff storing cannister causing a reduction in chaff propelling forces before cap disengagement. Furthermore, relatively high ejection pressure was heretofore found necessary to effect cap disengagement. The foregoing problems associated with the establishment of appropriate closure cap retention and disengaging forces to meet chaff dispensing conditions, was aggravated by currently available chaff camouflage ejection systems wherein a body chaff material is ejected in increments.
Accordingly, it is an important object of the present invention to provide a closure device for a chaff dispenser which will more reliably meet various conflicting chaff dispensing requirements by means of a relatively low cost closure construction and simple closure insertion procedure.